Hydraulic mechanism for a door operating system



Oct. 10, 1961 c. s. SCHROEDER ETAL 3,003,317

HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July a1, 1958 s Sheets-Sheet i INVEN'VIOR M 8. 8m Mm M 6% Oct. 10, 1961 c. s. SCHROEDER ETAL 3,003,317

HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 551, 1958 8 Sheets-Sheet 2 ELEC TRIC Moron A I'TOKPNEY Oct. 10, 1961 c. s. SCHROEDER ETAL 3,003,317

HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 31, 1958 8 Sheets-Sheet. 3

INVENTORS 6M 8. SW

NW /V. M

BY RM SW Oct- 10, 1961 c. s. SCHROEDER EI'AL 3, 0 7

HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 31, 1958 8 Sheets-Sheet 4 I7 I m \9 1n INVENTORS 6M 82 8M la/60 1 7. M

BY 2 W SM 4 Troy/v67 HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 31, 1958 Oct. 10, 1 1 c. s. SCHROEDER ETAL 8 Sheets-Sheet 5 INVENTORS i 6. 8M

1961 c. s. SCHROEDER ETAL 3,003,317

HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 31, 1958 8 Sheets-Sheet 6 0) y Ti 7.1a.

Oct. 10, 1961 c. s. SCHROEDER EI'AL 3,003,317

HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 31, 1958 8 Sheets-Sheet 7 Tic 2 1. no

Oct. 10, 1961 C. S. SCHROEDER ETAL HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Filed July 31, 1958 8 Sheets-Sheet 8 M1 10. H5 5 v 1 Q X I g I25 TD 55 z I m 1e 6d I TD 5' 0 I02 Hui,

W ij- 2 2- H4 FL g 15 ht f. INVENTORS SC I '31 5; 130 Mo$.ScA o1l/v g/ Mala, M- {M 5d :17 I BY W 8M 3 w E M ,4 rraq/vey United States Patent 3,003,317 HYDRAULIC MECHANISM FOR A DOOR OPERATING SYSTEM Charles S. Schroeder, Wynnewood, Mathias M. Check,

Stratford, and Raymond Schmid, Havertown, Pa., assiguors to The Yale and Tune Manufacturing Company, Stamford, Conn., a corporation of Connecticut Filed July 31, 1958, Ser. No. 752,355 9 Claims. (Cl. 60--52) This invention relates to an actuator for opening and closing a door, and, more particularly, to that class of actuators that utilize a usual form of door closer to open the door through the application of fluid pressure to a checking piston. The application of this fluid pressure will reverse the usual operation of the closer and cause it to open the door.

Heretofore, automatic actuators of this class generally required such means as a fluid pump, a motor, a fluid reservoir and considerable valving, part or all of which are remote from the actual operating unit. Such constructions necessarily require extensive plumbing to conduct the operating fluid from the reservoir to the actuator and back to the reservoir, and the installation of such devices is extremely diflicult and costly.

We have conceived by our invention a novel construction involving the utilization of a single actuator assembly including the operating unit, the fluid pump, the reservoir and the motor. Further we prefer to add to this assembly, means for limiting the operation of the actuator in an opening direction and for automatically holding the door open for as long as is required each time the door is opened.

A very important feature reisdes in that construction which makes possible the manual operation of the actuator as a normal closer. In our invention this requires an extremely novel arrangement of parts because of the necessity for obtaining a very varied operation, with a small, compact assembly.

As another feature of our invention, we provide a novel construction in which we utilize a door closer housing having a usual combination of closing spring that is loaded during the opening action, together with a piston and fluid. To this housing we apply a pump and a drive motor for operating the pump; the pump, through the fluid and piston, effecting opening of the door and loading of the spring.

A further feature of our invention resides in the provision of a time delay mechanism in the motor circuit to assure that the motor will operate to open the door fully once its circuit has been closed.

As an additional feature of our invention, we equip our actuator assembly with a limit switch for effecting the de-energization of the drive motor when the door travels the desired distance in its opening movement;

As a most important feature of the present invention, there are provided means for holding the door open for so long as a predetermined condition continues to exist. More particularly, we provide a solenoid that is energized to actuate a valve that closes a passage through which the piston must force fluid as it is moved to door closing position under the influence of the usual door closing spring. Thus, this solenoid controlled valve is effective to hold the door open so long as the solenoid remains energized; and we have devised means whereby the solenoid remains energized for so long as the traflic requires the door to be open.

As yet another particular feature of the invention, we use the solenoid controlled valve also as a pressure relief valve to relieve the door opening pressure in the event the door strikes an object or person during its opening movement. This same. feature relieves fluid- 3,993,317 Patented Oct. 10, 196i ICC pressure if the door is manually pushed towards a closed position while the solenoid is energized to close the valve. In this connection, we prefer to employ a poppet valve controlled by the solenoid through a pre-loaded spring so that only a predetermined end load may be imposed on the poppet by the solenoid. This construction enables the valve to serve not only as a hold open valve, but also as a pressure relief valve in the event that the fluid pressure on the pressure side of the pump becomes high enough to overcome the pro-loaded spring.

We have thus outlined rather broadly the more important features of our invention in order that the deunderstood, and in order that our contribution to the art .may'be better appreciated. There are, of course, additional featuresof our invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which our disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of our invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of our invention, in order to prevent the appropriation of our invention by those skilled in the art.

A specific embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawings.

In the drawings:

FIG.'1 is a perspective view of a door and flame equipped with our door actuator;

FIG. 2 is a cross section taken along line 22 of FIG. 1;

FIG. 3 is an elevation, partly broken away, to show the solenoid control valve;

FIG. 4 is an end view, partly broken away, of an end plate for supporting the motor;

FIG. 5 is a cross section taken along the lines 5-5 of FIG. 2;

FIG. 6 is a cross section taken along the lines 6-6 of FIG. 2;

FIG. 7 is a cross section taken along the lines 77 of FIG. 6;

FIG. 8 is a cross section taken along the lines 8-8 of FIG. 2;

FIG. 9 is a cross section taken along the lines 9-9 of FIG. 2;

FIG. 10 is a cross section taken along the lines 1010 of FIG. 3;

FIG. 11 is a top plan view of a portion of our door actuator showing the limit switch and the parts for actuating that switch as they appear when the door is in its closed position;

FIG. 12 is a view similar to FIG. 11 but showing the parts in the position they assume when the door is opening and the limit switch has been actuated to shut the motor olf;

FIG. 13 is a schematic View of a door actuator in accordance with our novel concept, showing several of the parts in their relative positions as the door opens;

FlG. 14 is a schematic view similar to FIG. 13, but illustrating the parts in open position and with the solenoid holding the door open;

FIG. 15 is a view similar to FIGS. 13 and 14 but illustrating the relative positions of the parts during the closing movement;

FIG. 16 is a view similar to FIG. 13 but illustrating manual opening of the door;

FIG. 17 is a further schematic view illustrating the operation of our actuator when the door is being pushed closed manually while the pump is operating to open the door.

FIG. 18 is a circuit diagram of the control circuits for operatingour dooropener illustratinginheavy lines those portions of the circuits that are energized in response to a particular condition; i

FIG. 19 is a circuit diagram similar to FIG. 18 illustrating the condition of the circuits under the control of the time delay mechanism;

. FIG; 20 is a circuit diagram illustrating the condition of the actuating circuits in response to another condition;

FIG. 21 illustrates the condition of the circuits in response to yet another condition.

FIG. 22 illustrates the condition of the circuits under still a further condition; and

FIG. 23 illustrates the condition of the circuits when the. motor and solenoid are energized by a manually operable switch in order to hold the door open for ex- ;tended periods of time regardless of the movement of traflic.

Referring now to the drawings, there is shown in FIG.

1 a door mounted in a door frame 11 for swinging The door actuator 12 of our, invention is movement. carried by the door in the same manner as is the usual door closer, and it effects actuation of the doorto open and closed positions through an operating arm 14. This arm is pivoted at one end to the frame 11' as at 15, and

for reciprocation in a piston chamber 18 formed in the housing 21, and has a central portion formed into a series of rack teeth 24 that engage the teeth of the piston 19 so that reciprocating movement of the piston 22 in the housing 21 will rotate the shaft 17 to effect swinging movement of the door through the operating arms 14 and 16.

It will be seen then that admission of Lfillld under pressure to the chamber 18 at the right side'of the piston 22, as viewed in FIG. 2, will cause the piston to move to the left, rotating the shaft 17 in a clockwise direction to swing the door open. The left end of the chamber is reduced as at 25 for engagement by an enlarged part 26 of the piston 22 as the piston approaches the end of its .openingstroke. A bore 27 communicates with the reduced end 25 of the chamber and communicates also with bore 29 that, in turn, enters the larger part 'of the chamber. An adjustable valve 30 controls passage of fluid from bore 27 through bore 29 to the large part of the chamber, or, around the enlarged part of the piston.

'Since the piston when moving toward the left in FIG.

2 must move the fluid out of the reduced portion 25 of a the chamber through passage 27, 29, and part of the around the piston head, a wall :a second operating arm 16 is pivoted to the other end valve 30, this construction provides an adjustable back 1 check for the opening movement of the door.

To return the door'to closed position, we provide a spring 31 carried by a supporting stud 32 that extends 'into chamber 18 from an end closure plug 34. The spring 31 bears against the plug 34 at one end, and

against the piston 22 atits other end. As is well understood by those persons skilled in, the art, the spring is loaded as' the piston moves towards the plug 34, and serves to drive the piston to its normal position as shown During the openingmovement of the'door, hydraulic the *piston' head by means that we shall subsequently described. To provide a path for the movement of fluid in FIG. 2 to swing the door to closed position when the .openi ng force is abated. 1 w

4 V of the housing 21 is thickened, as at 35, FIG. 2, and bored to provide a passage 36 that extends parallel to the chamber axis between an enlarged part of the housing that accommodates the pinion 19 and the right end of the housing. This end of the housing has an outwardly extending'porti on37 that serves in part to support a cylinder head or closure plug 39 formed, as shown in FIG. 6, to overlie the housing end including the extended portion 37. The head 39 has a hole 40 that registers with the passage 36 in the housing wall 35 to effectively extend the length of that passage. 7 7

Superimposed over the cylinder head 39 is a plate 41, shown in elevation in FIG. 5, that serves as a housing for a gear. pump, aswill-later be described. This plate is formedwith an opening 42that, has a pair of opposed lobesl42a and 42b for the pump gears, and an'arcuate slot 44 that communicates at one end with the lobes and, at the other end, with the hole. 40 in the cylinder head 39. It may readily be seen, therefore, that the fluid in the chamber 18 may flow freely .to the pumpthrough the passage 36 in the housing, the hole 40 in the cylinder head and the arcuate slot 44 in the plate 41, this fluid path thus constituting the suction side of the pump.

Fluid from the suction side of the pump is pumped into a high pressure slot 45 in the plate 41 and thence into a stepped bore 46 in the cylinder head 39 that communicates at one end with the slot 45, and at the other end with ,the chamber 18 in front of the piston head. As we have mentioned, and as shown in FIGS. 2 and 7, this bore 46 is stepped and thus provides a seat for a spring loaded ball check 49. When the pressure in the slot 45 reaches a predetermined level, the ball check is unseated to admit fluid into the chamber 18. The slot 45 and the stepped bore 46 therefore constitutethe pressure side of the pump.

An end plate 50 is mounted against the outer face of the plate 41 and an electric motor 51 is supported adjacent this plate by a plurality of studs 52 thatpass through the plates-50 and 41, and the cylinder head 39, and are threadedly engaged in the housing 21. The end plate 50 is bored at 54 to receive the motor drive shaft 55- and a recessed boss 56 on the end plate provides a packing gland toprevent the leakage of fluid around the shaft 55. The drive shaft extends intothe opening .42 in the plate 41 where it serves to drive the pump gears 57.

To, review the operation of the mechanism thus far described to swing the door from a closed to an open position, the motor 50 is energized causing the pump gears-57 to pump hydraulic fluid from its suction side, through the passage 36, the hole 40 and the slot 44 and into the high pressure slot45 and the bore 46. The force of the fluid in the bore 46moves the ball check 49 off its seat against the influence of the spring 48. Fluid under pressure therefore is admitted into the chamber 18 in front of the piston 22driving that piston towards the closure plug 34 whereby it loads the spring 31 and rotates the shaft 17 through the rack 24 and pinion 19 to swing the door 10 open through operating arms 14 and 16. As the door approaches full open position, it is back checked in the well-known manner by the action of the valve 30 restricting the flow of fluid between bores 27 and 29, as has already been described.

It is .desirable that the door be adapted for manual opening in the event of a power failure. For this purpose, we refer to FIGS. 6 and 7, from which it will be seen that we provide in the cylinder head 39 a stepped bore 53, similar to bore 46, but passing through the head 39 in a location to placethe chamber 18 in communication with the suction side of the pump, preferably the arcuate slot 44 in the plate 41. A ball check 58is biased against the step to maintain the bore normally closed. With such a construction, if the door is manually pushed towards its openposition, the'pinion 19 will draw the piston back compressing the spring 31. Fluid'willpass from that portion or the chamber is behind the piston, through the U passage 36, the arcuate slot 44, past the ball check 58 and through the bore 53 into the chamber 18 in front of the piston.

,We shall now describe the means by which the fluid is returned from the high pressure side or front of the piston to its low pressure or reservoir side in order to permit the spring 31 to effect closing of the door. As best shown in FIGS. 2, 3 and 9, the right end of the chamber 18 communicates with a pair of lateral bores 59 and 60 that are longitudinally offset relatively to the chamber and that are interconnected at 61 (FIG. 9). These bores 59 and 60 are provided with adjustable valve members 62 and 64, respectively, for restricting the flow of fluid from the chamber 18, and the bore 59 communicates with a passage 65 in the outwardly extending portion 37 of the housing 21 as clearly shown in FIGS. 2 and 9. This passage 65 is efiectively extended through the cylinder head 39, the plate 41 and into the end plate 50 by the registering holes 66 and 67 in the cylinder head 39 and plate 41, respectively, and the bore 69 in the end plate 59. As shown in FIG. 4, the bore 69 in the end plate 59 communicates with a lateral bore 70 in that plate that in turn communicates with a port 71 opening into a hole 72 in plate 41 (FIG. This hole 72 communicates with the arcuate slot 44 through another slot 74.

As we have already shown, the arcuate slot 44 communicates with that part of the chamber 18 behind the piston head that constitutes the fluid reservoir through the hole 40 in the cylinder head 39 and the passage 36 in the housing 21.

It is thought best now to review the flow path of fluid in the mechanism that We have thus far described during the closing movement of the door. As the spring 31 moves the piston 22 towards the cylinder head 39 to move the door to closed position, the fluid in the high pressure side of the chamber, that is in front of the piston, is forced through bore 59 and into passage 65, the valve 62 being set to regulate the flow so as to permit the piston to move quickly. After the piston head passes the bore 59, fluid remaining in front of the piston is forced through the bore 60, the interconnection 61, the bore 59 and into the passage 65, the valve 64 being set to slow or check the movement of the piston and hence the door. From passage 65, the fluid flows through the holes 66 and 67 in the cylinder head 39 and plate 41, respectively, the bores 69 and 70 and the port 71 in the end plate, and into the hole 72 in the plate 41, through slot 74 and the arcuate slot 44, into hole 40 in cylinder head 39 and thence through the passage 36 in the housing 21 and finally into the low pressure side of the chamber 18 behind the piston head.

We have stated that we provide means for automatically holding the door open for as long as is required each time the door is used, and that to implement this feature of our invention, we utilize a solenoid that is energized to close a valve to prevent the flow of fluid from the front or high pressure side of the piston to the rear or low pressure side. As shown in FIGS. 2 and 3, solenoid 75 is conveniently fastened to the housing in opposed relation to a lever 76 that is supported for pivotal movement on a pin 77. The lever 76 engages the solenoid armature 79 so that when the solenoid is energized to retract its armature, the lever 76 will pivot in a counterclockwise direction, as viewed in FIG. 3. We further provide a plunger assembly 8!, that includ s a rod 81 carried in telescoping relation with a second rod 82, the degree of relative movement of these rods 81 and 82 being limited by a pin 84 on the inner end of rod 81 extending into a slot 85 in rod 82. The exterior of the rod 82 is screw threaded to adjustably retain collars 86 and 87. A spring 88 is disposed between one end of the adjustable collar 86 and an enlarged head at the remote end of the rod 81. The spring load and the length of the plunger assembly are each adjustable by setting collars 86 and 87, respectively, to establish a predetermined relief pressure and to compensate for dimensional variables in the physical components. It will be observed that the plunger assembly is supported for sliding movement in a bore 89 in the extended portion 37 of the housing 21 with one end abutting the lever 76 and the other end abutting a flexible diaphragm or gasket 90 between the end of the housing 21 and the cylinder head 39.

As shown in FIGS. 3 and 6, the cylinder head 39 has a hole 91 therethrough that is coaxial with the bore 89 in the housing 21 on one side, and with the hole 72 in the plate 4-1 on the other, and that is flared outwardly at its end adjacent the gasket 90. Disposed this hole for sliding movement is a poppet 92. The poppet has a section of reduced diameter extending through the hole 72 and tapered at its end to seat against the sides of the port 71 in the end plate 50 which, it will be remembered, opens into the hole 72.

As will be appreciated from the previous detailed description of the flow path of fluid from the high to the low pressure side of the piston, as when the door is moving from open to closed position, that fluid flows from the lateral bore 70 in the end plate 50, through the port 71 and into the hole 72 in the plate 41 (FIGS. 4 and 5), from which it moves through slots 74 and 44 and passage 36 to the reservoir or chamber 18. It will be further appreciated that if the fluid is prevented from escaping from the high pressure of right end of the chamber 18, as viewed in FIG. 2, the spring 31 could not force the piston forward to close the door. Accordingly, upon energization of the solenoid 75 to retract the armature 79, the lever 76 pivots in a counterclockwise direction about the pin 84 to urge the plunger assembly 80 to the right, as viewed in FIG. 3. Such movement of the plunger assembly is transmitted through the flexible gasket 90 to the poppet 92 which seats against the side wall of port 71 closing ofl return communication between the high and low pressure sides of the piston and preventing the piston from moving under the influence of the spring 31 to close the door.

We have also indicated that the solenoid controlled valve may be utilized as a pressure relief valve to relieve the opening pressure in the event the door strikes an object or person during its opening movement. For this purpose, reference is made to FIGS. 4 and 5 showing a passage 94 that communicates with the high pressure slot 45 in the plate 41. A spring loaded ball check 95 normally blocks fluid flow from passage 94vinto the lateral bore 70 with which the passage communicates.

Should the door fail to open because of an obstruction while the motor is driving the pump, and while the solenoid is energized to close the poppet valve, fluid will flow from the high pressure slot 45 through the passage 94, past the ball check 95, into the lateral bore 70 and the port 71 forcing the poppet to unseat. The fluid Will therefore be admitted to the hole 72 in the plate 41 from which it will pass through the slots 74 and 44 to be recirculated by the pump along the flow path just described for so long as the door remains obstructed and the motor and solenoid energized.

It would be well to draw attention here to the fact that if an attempt is made to close the door manually, that is, to push it to a closed position, while the solenoid is energized, the door will actually move towards its closed position as soon as sufiicient fluid pressure is generated to unseat the poppet against the force of its spring 88. In such a case, of course, the flow path is identical with the flow path described with reference to closing action eifected by the spring 31.

We now draw attention to FIGS. 11 and 12. in connection with which we shall describe the means for de-energizing the drive motor when the door has travelled the desired distance in its opening movement. In FIG. 11 we illustrate the condition of the various parts when the motor is energized and the operating arm 16 is moving counterclockwise, as viewed, to open the door.

A cam plate-96 is mounted on the pinion shaft 17 and rotates with that shaft. This cam plate has a cam surface 97 that is formed to rotate a lever 99 in a counterclockwise direction, as viewed, about its pivot pin 100 to the position shown in FIG. 12 as the shaft 17 is ro- '8 time delay relay TD to open the switch TDI'fo'ur secondsafter the relay .ID is energized. Inthis way, the door will be opened fully and will be held open by the solenoid 75 for two'seconds after reaching full open position, even if the person steps olfmat 1 immediately after establishing the first contact, or in the event that he steps on a dead spot in the mat after making the first contact. In such a case, the condition that the circuits will assume is shown in FIG. 19 wherein the switch M1 is open, but relay 5 remainsclosed due to delayed opening of switch TD1, whereby the by-pass circuit remains adjustment screw 105 is also mounted on the lever 99 V and bears against the surface of the spring 101.

'When the operating arm 16 and cam plate 96 rotate a'suflicient distance in door opening direction, the leg 1101b of the spring will depress the plunger 104 to open the motor circuit. It should be noted that since the cam plate 96 has a long camming surface 97 relatively to pinion rotation, and a high lift relatively to plunger movement, it is possible to adjust the screw 105 to set the spring leg 101b relatively to the switch plunger and to thereby regulate the motor shut off position to correspond with the desired maximum door opening position.

Having described the mechanical features of one embodiment of our invention, we shall now describe the electrical control'circuits that are illustrated in FIGS. 18 to 23, in each of which the heavy lines indicate that portion of the circuit that is energized under a particular condition to be described.

Referring momentarily to 'FIG. 1, it will be seen that we have chosen toutilize several floor treadles or mats that are actually deformation switches of a commercially available type. Such switches make contact by placing a weight anywhere on the mats, and contact is broken when the weight is removed. While we show three mats, two of these mates perform the same function so that they are both represented by the reference numeral 1, and are disposed one on each side of the door; and on that side of the frame 11 in which the door swings, we have placed a mat 2 that separates the mats 1. Of course, it will be understood that other forms of circuit making apparatus such as photoelectric cells or push buttons may be employed, and that the mats are merely the preferred form.

Referring now to FIG. 18, there is shown a primary circuit 110 and a secondary circuit 111 that is energized by the primary circuit'through the transformer 112.

As a person approaches the door from either direction, he first steps on a treadle or mat 1, represented in FIGS. 18 to 23 as the switch M1, establishing a circuit between the secondary transformer winding, conductors 114 and 115,-the normally closed switch 7a, relay 5, r

and conductors 117 and 119. Energization of the relay 5 closes switch 5a completing a circuit from conductor 114, through conductor 120, relay TD, and conductors 121 and 119 back to the transformer winding. This same relay 5 simultaneously closes switch 5b establishin a by-pass circuit around the mat 1 through conductor 123 and the normally closed switch TD1 to the conductor 115. Energization of relay 5 also closes switch 5c in the primary circuit completing a circuit through conductors 12-2 and 124, the solenoid 75 and conductors 125 and 126. Switch 511, also in the primary circuit, is also closed completing yet another circuit through conductors 122 and 127, the motor starting relay 129, the motor field coil 130, the limit switch 102, and the conductor '126. In other words, by stepping on either of the mats 1, a person starts the motor, thereby moving the door towards open position, energizes the solenoid 75 to move the poppet 92 to close the port 71, completes a by-pass circuit around the mat 1, and energizes the relay TD, which is a time delay relay that opens the switch TD1 in the by-pass circuit after a pre-determined period of time. T 0 illustrate, we have chosen to arrange the mechanism to open the door in two seconds and have set the energized to, in turn, maintain the motor and solenoid energized until the door reache'sthe desired open position, at which time the switch 102 opens in the manner earlier described to stop the motor, while the solenoid remains energized to hold the door open until relay TD opens the switch TD1 to deenergize the relay 5 and open switches 5a, 5b, 5c and 5d. v

Turning now to' FIG. 20, we have illustrated the condition of the circuits when, in normal use, a'person is stepping from one of the mats 1 to the mat 2. The switch M1 is open, the timedelay circuit is closed by switch TD1 under control of the relay TD and the solenoid and motor 51 are energized as before. Additionally, however, the sWitch'M2, representing mat 2, is closed completing a circuit from conductor 114 through conductor 129, relay 6 and conductors 117 and 119 to the secondary'winding of'the transformer 112. Energization, of this relay 6 closes switch 6a, that is in parallel with switch 5a, and also closes switches 6b, 6c in parallel with switch 50, and 6d. Since, when stepping from mat 1 to mat 2, the mat switches M1 and M2 will be momentarily'simultaneously energized, current will flow from conductor 129 through switches 6b and 5b to conductor and relay 5 holding that relay energized even after the foot is lifted off mat 1. In other words, the conditions created by energization of the relay 5, as described heretofore, are maintained with the addition of the energization of relay 7 through conductor 129, switch 6d and conductors 130, 131, 121 and 119, to open the normally closed switch 7a in conductor 115. This switch 7a, controlled by the relay 7, provides a safety feature that will be described with reference to the condition illustrated in FIG.-21. V

Referring now to FIG.'21, we show the condition of the circuits should a person step on mat 2 without first stepping on one of the mats 1. The relay 6 is energized through the conductors 114, 129, 117 and 119, closing the switches 6a, 6b, 6c and 6d thereby energizing the time delay'relay TD and the relay 7 that opens the switch 7a. Since the motor circuit is not energized, the

door will not open and, as a safety feature, should a second person step on either of the mats 1 while the first person remains standing on mat '2, directly in the path of the door, the open switch 7a prevents completion of a circuit through switch M1 to the motor energizing relay 5. If the door had been open at the time the user stepped directly on to mat 2, energization of the relay 6 would close switch 66 to energize the solenoid 75 closing the poppet valve 92 and holding the door open.

As shownin FIG. 22 if, after setting the condition described with reference to FIG. 21, the user then takes a second step on mat'2 and hits a dead spot, he will remain protected dueto the fact that the time delay switch TD1 remains closed until opened by the time delay relay seesaw ing it open for an indeterminate period of time. For this purpose we provide in the conductor 122 a manually operable switch 132 that connects the conductors 122 and 124 to energize the solenoid 75 while simultaneously connecting the conductors 122 and 134 to energize the motor 51. The motor swings the door open until the switch 162 in conductor 134 is opened in the manner already described whereupon the motor is de-energized. However, the spring 31 is unable to push the piston 22 to close the door so long as the switch 132 remains closed to maintain the solenoid 75 energized.

We have provided schematic representations of our actuator in FIGS. 13 and 17 in order to facilitate an understanding of its overall operation that we are about to describe.

Referring to FIG. 13, we show the operation of the various parts when one of the switches M1 is closed, as by stepping on one of the mats 1. It will be recalled that closing either switch M1 establishes circuits for energizing the motor and the holding solenoid. Operation of the motor causes the pump gears 57 to draw fluid from the chamber 18 behind the piston through the passage 36, slot 45 and through bore 46 past ball check 49 and back into the chamber 18 in front of the piston. The piston is therefore moved towards the left, as viewed in FIG. 13, until it closes off the passage of fluid through the bore 29, whereupon the bore 27 restricts the flow of fluid into the pasage 36 to serve as a back check. Since the solenoid was energized simultaneously with the motor, the valve 92 has been moved to the left by the lever 76 to close port 71 during that part of the operation described thus far.

FIG. 14 corresponds to the condition that exists when the user reaches mat 2. The solenoid remains actuated, retaining the poppet valve 92 in closing relation to the port 71 so that the main spring 31 is unable to move the piston to the right, as viewed, therefore efiectively hold ing the 'door open.

In FIG. 15 we illustrate the piston moving to the right under the influence of the main spring after the user has passed through the door. During the major portion of its closing stroke, the piston 22 forces fluid through the bores 59 and 60, the bores represented by the reference numerals 65 to 69, the port 71, past the poppet 92, wmch has now moved to open position due to the de-energization of the solenoid, and through passage 36 to the chamber behind the piston. After the piston has traversed the long portion of its stroke, it will close off the bore 59 so that the remaining fluid must pass through the bore 6% which is restricted by the valve member 64 to check the closing movement of the door.

As we have stated, in the event of a power failure, our door actuator will operate as a conventional door closer, the opening movement of the door being by manual pressure.

FIG. 16 illustrates schematically, the movement of the piston and the flow of fluid as the door is opened manually. As the piston is moved to the left by rotation of the pinion through the operating arms, fluid flows through the passage 36, in the same manner as has just been described with reference to FIG. 13. However, since the pump is not operating, the pressure in the fluid generated by movement of the door causes the ball check 58 to open the port 53 that communicates with the passage 35 on the suction side of the pump thereby admitting fluid to the chamber 18 in front of the piston.

In FIG. 17 we show what happens when the door is being pushed manually to a closed position while the pump is operating in a manner to open the door while the solenoid urges the poppet 92 to close the port 71. As we have already stated, this poppet 92 serves not only as a holdopen valve, but also as a pressure relief valve, this latter feature being provided by the adjustable spring 88. As the door is manually forced towards a closed position, the piston forces the fluid out of the chamber 18 through the bores 59 and 60, the pressure in the front of the chamber preventing the ball check 49 from opening the port 45. The pump will therefore generate enough pressure to open the ball check in the bore 70. Fluid passing through the bores 59, 60 and 70 will merge in the passage represented by the numerals 65 to 69, under sufficient pressure to force the poppet 92 to open the port 71, against the action of the spring 88. Fluid will therefore flow past the poppet and into the pasage 36, some of the fluid being recirculated along this route by the pump while the remainder of it will flow back into the chamber 18 behind the piston.

From the foregoing description, it will be seen that We have provided a door actuator utilizing a single, small, compact assembly that includes the operating unit, the pump, the reservoir and the motor as well as means for limiting the operation of the actuator in an opening direction and for automatically holding the door open for as long as is required each time the door is opened. it will further be seen that we provide a time delay mechanism to assure that the motor will operate to fully open the door once the motor circuit has been closed and to assure further that the door Will remain open for a predetermined period of time. Our arrangement also assures that the door will remain open even after expiration of the time delay period, if the traific so requires it. Furthermore, We have provided a pressure relief valve that will operate to relieve the opening pressure in the event that the door strikes an object or person during its opening movement or is manually pushed in a closing direction while the motor is energized to operate the door in an opening direction. It will also be seen that We incorporate a safety feature into our actuator whereby a person standing in the path of the door when the door is closed automatically prevents the door from being actuated.

Upon consideration of FIG. 10, those persons skilled in the art will readily appreciate that the door actuator of our present invention is reversible by merely inverting the pinion 19. Also, our door actuator maybe mounted on the door, as shown in FIG. 1, or on the door frame or on brackets of the type frequently used in mounting door closers, or in exposed or concealed floor mountings.

t is believed that the construction and operation of our novel contribution will now be fully understood and appreciated by those persons skilled in the art.

We now claim:

1. In a door actuator assembly comprising a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a fluid pump operable to effect movement of said piston in an opposed direction and a motor for operating said pum a passageway for exhausting fluid from said chamber as said piston is moved by said spring, and valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render said spring ineflective, a control circuit having a solenoid operable to move said valve means to closed position, a relay effective to energize said solenoid and motor, means responsive to a particular condition for controlling operation of said relay, and time delay means for maintaining said solenoid and motor energized for a predetermined period of time after the occurrence of said particular condition.

2. In a door actuator assembly comprising a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a fluid pump operable to effect movement of said piston in an opposed direction and a motor for operating said pump, a passageway for exhausting fluid from said chamber as said piston is moved by said spring, and valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render said spring ineffective, a control circuit having a solenoid operable to move said valve means to closed position, a relay effective to energize said solenoid and motor, means responsive to a particular condition for controlling operation of said relay, time delay means for maintaining said solenoid and motor energized for a predetermined period of time after the occurrence of said particular condition, and switch means effective to deenergize said motor when the pistonhas moved a predetermined distance.

3. In a door actuator having a housing, a chamber in said housing, a piston movable in said chamber and a passageway for exhausting fluid from said chamber as said piston is moved, and valve means said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to prevent movement of said piston, a control circuit having a solenoid operable to move said valve means to closed position, a relay effective to energize said solenoid, means responsive to a particular condition for controlling operation of said relay, and a yieldable connection between the said valve means and said solenoid which yields to allow said valve means to open when a predetermined pressure is applied to said valve means.

4. Ina door actuator assembly comprising a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a fluid pump operable to eflect movement of said piston in an opposed direction and a motor for operating said pump, a passageway for exhausting fluid from said chamber as said piston is moved by said spring, and valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render said spring ineffective, a control circuit having a solenoid operable to move said valve means to closed position, a relay effective to energize said solenoid and motor, means responsive to a particular condition for controlling operation of said relay, time delay means for maintaining said solenoid and motor energized for a predetermined period of time after the occurrence of said particular condition, and means responsive to the occurrence'of a second condition for maintaining said solenoid energized for so long as said second condition continues to exist. 7

5. In a door actuator assembly comprising a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a passageway for exhausting fluid from said chamber as said piston is moved by said spring, a valve in said passageway movable to close the same to prevent the flow of fluid therethrough to prevent movement of said piston, under the influence of said spring, a fluid pump operable to etiect movement of said piston in a z direction opposed to the direction of movement thereof eflected by said spring'and a motor for operating said pump, a control circuit having a solenoid operable to move' said valve to a closed position, a solenoid and motor controlling relay effective to energize said solenoid and motor, means responsive to a predetermined condition for controlling operation of said relay, and means responsive to a second condition for preventing energization of said motor upon the subsequent occurrence of said first named condition while said second condition continues to exist. 7

6. In a door actuator assembly comprising, a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a fluid pump operable to effect movement of said piston in an opposed direction and a motor for operating said pump, a passageway for exhausting fluid from said chamber as said piston is moved by said spring, valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render said spring ineffective, first control means to simultaneously move said-valve means to close said passageway and to energize said motor, and second control means independent of said first control means to prevent energization of said motor by said first control means.

7. In a door actuator assembly comprising, a housing, a chamber in said housing, a piston movable in said chamber, a-spring in said housing for urging said piston in one direction, a fluid pump operable to effect movement of said piston in an opposed direction and a motor for operating said pump, a passageway for exhausting fluid from said chamber as said piston is moved by said spring, valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render said spring ineifective, first control means to simultaneously move said valve means to close said passageway and to energize said motor, and second control means preventing energization of said motor by said first control means when said piston is in a predetermined position. 7 a

8. In a door actuator assembly comprising, a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a fluid pump operable to efiect movement of said piston in an opposed direction and a motor for operating said pump, a passageway for efiausting fluid from said chamber as'saidpiston is moved by said spring, valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render said spring ineflective, first control means to simultaneously move said valve means to close said passageway and to energize said motor, and second control means to move said valve means to close said passageway and to prevent energization of said motor by said first control means.

9. In a door actuator assembly comprising, a housing, a chamber in said housing, a piston movable in said chamber, a spring in said housing for urging said piston in one direction, a fluid pump operable to effect movement of said piston in an opposed direction and a motor for operating said pump, a passageway for exhausting fluid from said chamber as said piston is moved by said spring, valve means in said passageway movable to close the same to prevent the flow of fluid therethrough and therefore to render saidspring ineffective, first control means to simultaneously move said valve means to close said passageway and to energize said motor, and second control means to move said valve means to close said passageway when said first control means is not actuated.

References Cited in the file of this patent UNITED STATES PATENTS 1,836,813 Rankin Dec. 15, 1931 2,099,886 Hasson et al. Nov. 23, 1937 2,276,338 Potter et al. Mar. 17, 1942 2,292,336 Farnham Aug. 4, 1942 2,330,005 Odenthal Sept. 21, 1943 2,399,294 Ray Apr. 30, 1946 2,459,695 Griffin Jan. 18, 1949 2,495,669 Cannon Jan. 24,1950 2,579,742 Kaufman Dec. 25, 1951 2,665,153 Teichmann Jan. 5, 1954 2,800,323 West et al. July 23, 1957 2,869,861 Carlson Ian. 20, 1959 

